It is known to create a two phase mixture in personal care products. In such multiphase mixtures, one of the phases is an aqueous phase and the other phase will comprise a hydrocarbon oil or other oily substance which is substantially immiscible with the aqueous phase. When agitated, the two phase mixture will distribute itself in a single dispersion and when allowed to settle, the aqueous and oils phases will separate into distinctly separate layers. U.S. Pat. No. 3,718,609 to Weimer, discloses a liquid detergent composition having an aqueous layer and a layer of a liquid, water-immiscible oily material which, when shaken, forms a temporary oil-in-water emulsion. U.S. Pat. No. 3,810,478 to Olson, Jr. et al. discloses a two-phase shampoo composition made by preparing substantially polar and lipophilic portions of a shampoo composition, and mixing them together.
Attempts to create multiphase mixtures which contain aqueous phases have not been successful without the further addition of special purpose components such as thickeners and detergent builders to achieve the multiphase appearance. These compositions consequently comprise components which potentially interfere with the timely separation of the homogenized product back into its aesthetically preferred multiphase aspect, and in some instances (i.e. the use of a detergent builder) when employed in a personal cleanser can actually irritate the skin.
U.S. Pat. No. 6,429,177 to Williams et al. discloses a cleansing system comprising a transparent or translucent package containing a personal product composition having 2 or more visibly distinct phases. When agitated, the composition forms a visible single phase. The composition comprises from 5–35 weight percent surfactant, 1 to 12 weight percent of a thickener, 4 to 20 weight percent of a polyalkylene glycol, and a non-chelating mineral salt which is present in an amount which is sufficient to induce at least two distinct aqueous layers that are present in a volume ratio of upper to lower phase of from 4:1 to 1:4.
EP 0,116,422 (assigned to Reckitt & Coleman) and EP 0,175,485 (assigned to Reckitt & Coleman) disclose multi-layer liquid compositions in which two liquids are dispersible and which separate on standing. The compositions require sodium hexametaphosphate as detergent builder to facilitate the formation of the two phases.
In a personal cleansing system for cleansing human skin and hair, a multiphase composition is sought which will provide a clean feeling, which is not oily or greasy, and which leaves no oily or greasy residue on the skin. Furthermore, the multiphase composition must quickly transition between a stable multiphase appearance and upon agitation create a single application phase. In the single application phase, the multiphase composition may be further agitated or intimately mixed by some mechanical device to form a uniformly dispersed or single application phase such as a liquid, a foam or a lather. Still further, after such agitation, the uniformly dispersed phase will quickly return to the stable multiphase appearance.
It is an objective of the present invention to achieve the multiphase appearance of the multiphase composition without employing thickeners (which would retard the separation process unduly) or detergent builders which may irritate the skin and reduce the effectiveness of the multiphase composition as a cleansing composition.
It is an objective of the present invention to provide an aqueous multiphase composition which after agitation and formation of a single application phase, rapidly returns to its multiphase appearance.